Can anyone recommend a cleaner to remove cat vomit from pre finished oak from bruce ?

You mean the typical hardwood floor cleaner will not work? Like Bona hardwood floor cleaner? I'd have to ask then, what kinda cat is this and what has he/she been eating? In all seriousness, is the finish an older Bruce waxed finish? Or a newer urethane finished floor?

its the newer bruce dundee gary .. i was there to measure for 3 other rooms when he just left and came back with a rag with water , i told him to stop and would let him know what to use .. Never thought of Bona [ thanks ] ..
someone on another board suggested mineral sprits ..

The finish, may well be etched. Vomit has a lot of acid in it. It can eat through the finish and damage the wood beneath.

Why not do a R&R on the affected boards if the stain will not come out.